Many patents have been issued on saw chain and cutting teeth for saw chains for cutting wood. The action of a cutting tooth cutting through the wood fibers of a tree or log have been studied and restudied in order to attain the best cutting chain for that purpose. The objective of the present cutting chain is to cut up bales of hay as an aid to the cattle raising farmer.
Whereas one may assume that cutting hay bales would be a simple process for a wood cutting chain, such is not the case. Hay is comprised of long grass or hay strands, small in diameter, flexible and with a low point of combustion. Hay bales often are formed by rolling the grass strands into a large, e.g. six feet in diameter, tightly compacted mass that is tied together. The bales are stored in that form until many months later, generally in the winter, when they are taken out of storage to a cattle feeding lot, and then broken apart for feeding. The problem encountered is that the hay has become molded into the shape of the bale and simply untying the bale does not accomplish the loosening of the hay as required for feeding.
The apparent answer is to cut the bale apart. The seemingly optimum cutting tool for this purpose is a chain saw. However, prior to the present invention, the chain saw equipped with any of the dozens of wood cutting chains available, have not provided a satisfactory solution.
A hay bale is like wood in at least one respect. Cutting through the hay bale is not easily done with a slicing action like that of a knife. It requires a trenching action like that of a saw. That is, material must be removed to generate a kerf that permits the entry of the cutting tool.
In many other respects, cutting a hay bale is not like cutting a log. The wood fibers in a log are always aligned in the same direction and they are adhered together. The cutting tooth of a saw chain the wood during the trenching action in the form of chips that are flung out and away from the cutting teeth of the saw. The grass strands of a hay bale are criss-crossed throughout the bale and they are not adhered together except by simple compression. As strands of grass are cut, they are freed of the bale and separated from other strands. In the conventional wood cutting chain, some of these strands become captured in and around the components of the saw chain and carried back into the chain saw housing. The strands could build up in the housing and cause plugging and ultimately a fire hazard.
Prior attempts to solve the problem have included modifying the cutting tooth configuration by sloping the cutting edge rearwardly, to simulate a slicing action. This reduces the likelihood of grass strands getting caught up on the cutting edge, but does not eliminate the problem. Furthermore, it creates difficulty in cutting. The side plate cutting edge which cuts the side walls of the kerf acts like a ramp and the operator must exert considerable inward force to make the cutting chain cut.
Other modifications have been tried and abandoned and the outcome is that prior to the present invention, no one has conceived of a satisfactory cutting chain for cutting hay bales.